This invention relates to a process for preparing aromatic alkanols.
In the known process of preparing the commercially important aromatic alkanol 2-phenylethanol by reaction of the Grignard reagent, phenylmagnesium halide, with ethylene oxide, significant quantities of chlorohydrins and, some cases, initial rearrangement of the ethylene oxide to the aldehyde or ketone followed by reaction with the Grignard reagent, accompanies the desired reaction. Magnesium halide, M.sub.g X.sub.2, is thought to be responsible for most of these undesirable reactions.
U.S. Pat. Nos. 3,228,831 and 3,385,886 disclose compounds of the general formula ##STR1## wherein R' represents alkyl (C.sub.3 -C.sub.4), pentyl (except n-pentyl), alkylene (C.sub.2 -C.sub.4), cycloalkyl (C.sub.5 -C.sub.7) optionally substituted by a methyl group in the 1-position, alkoxy (C.sub.2 -C.sub.3), alkylthio (C.sub.1 -C.sub.3), allyloxy, phenoxy, phenylthio, cyclohexyloxy and cyclohexylthio when R.sup.2 is hydrogen; or R' represents alkyl (C.sub.2 -C.sub.5), branched alkyl (C.sub.6 -C.sub.7), cycloalkyl (C.sub.3 -C.sub.7) optionally substituted by a methyl group in the 1-position, alkoxy (C.sub.2 -C.sub.5), alkylthio (C.sub.1 -C.sub.5), alkenyloxy (C.sub.3 -C.sub.4), alkenylthio (C.sub.3 -C.sub.5), phenoxy, phenylthio, cycloalkyloxy (C.sub.3 -C.sub.7), cycloalkylthio (C.sub.3 -C.sub.7), alkylene (C.sub.2 -C.sub.4) and halogen when R.sup.2 is methyl; X represents CH.sub.2 OH, COOR.sup.3 wherein R.sup.3 represents hydrogen or alkyl (C.sub.1 -C.sub.4) optionally substituted. These compounds, including the non-toxic inorganic and organic salts of the acids, i.e., those compounds wherein X is COOR.sup.3 in which R.sup.3 is hydrogen, are said to possess anti-inflammatory and/or analgesic and/or antipyretic properties. One particular compound within the foregoing general formula, ibuprofen (i.e., 2-(4-isobutylphenyl)propionic acid), which possesses the structure ##STR2## is a widely utilized anti-inflammatory agent. Several methods are disclosed in these patents for the preparation of this and related propionic acids, i.e., hydrolysis of a nitrile intermediate, decarboxylation of a dicarboxylic acid intermediate, hydrolysis of an ester intermediate, dehydration of a hydroxy acid intermediate and simultaneous dehydration of a hydroxy nitrile with hydrolysis of the nitrile group to a carboxylic acid group. These patents also disclose the preparation of the alcohols ##STR3## wherein R.sup.1 is, inter alia, isobutyl, by reaction of the Grignard reagent R.sub.1 PhMgCl with ethylene oxide. It is highly probable that this last-mentioned reaction is also accompanied by the same sort of undesirable side reactions as those discussed above in connection with the known synthesis of 2-phenylethanol employing a Grignard reagent.